The provision of wireless network services to user terminals typically requires a so-called subscription with an operator of the wireless network providing the services. The persons operating the user terminals and having such subscriptions are called subscribers.
Network operators conclude roaming agreements with each other to permit their subscribers to also access the wireless networks of the other operators. The operator that manages the subscription for a particular user terminal is called home operator, and the home operator's network is called home network. An operator that provides network services to a user terminal governed by a roaming agreement is called visited operator, and the visited operator's network is called visited network.
A user terminal is roaming when it is serviced in a visited network in which no subscription information for the user terminal is available. Before a roaming user terminal can access the services of the visited network, the required subscriber information must first be requested from the home network so that the subscriber can be properly authenticated, any authorization for using the services of the visited network can be checked, and the services can be charged to the subscriber.
Subscriptions often include so-called Service Level Agreements (SLAs) that grant particular data rates, data volumes or other preferred conditions to the associated subscriber. Customer care systems, on the other hand, collect various Key Performance Indicators (KPIs), service usage data, location data and other information to answer and promptly act on customer requests and complaints. The customer care systems thus permit SLA validation, for example by comparing the actual data rates provided to a subscriber's user terminal with a data rate guarantee as defined in the subscriber's SLA.
It has turned out that SLAs cannot be reliably verified in roaming scenarios and, as a result, it is not always possible to immediately take associated technical measures (such as data rate or data volume increases). This applies both to the scenario in which a user contacts a customer care system of a visited network while roaming and the scenario in which a user contacts a customer care system of the home network afterwards for problems that were encountered while roaming. The resulting drawback is believed to be become more pronounced in the future as roaming fees will decrease and, therefore, roaming will become increasingly popular in terms of the number of roaming users and the traffic volumes generated by roaming users.